Disclaimer: I do not in fact own Harry Potter or Blue Exorcist. I mean really if I did, would I be writing fanfiction? NO! I would be a beach somewhere drinking sangria and laughing! Hahahahaha! – Like that but more rich.

Warnings: Spoilers if you have never read or watched Blue Exorcist, Harry is ridiculously smart, and a little fluff.

Beta: FEARMEfrancis

A/N: Last time I checked there was no category for this, so I decided to get the ball rolling! Do tell me what you thought since another HP/Blue Exorcist story is in the works. I'll even make a poll! Polls are fun :)

Evolving Exorcists

Harry didn't know what they were, but ever since he could remember he had always seen demons. He never knew what they were called, just that they took many forms, and they gave off a certain aura. Some were friendly to Harry and some were downright mean.

He had come across a demon in his Aunt's garden that had tried to make his promise to always care for the garden. Harry was about it but something told him he shouldn't. He had refused and the demon got angry, but luckily his aunt had come outside and Harry made a quick escape. Twenty minutes later he saw a weird person enter his Aunt's garden and the demon left. After that he was more cautious about interacting with them.

He finally learned what they were when he was six years-old, and he was on a shopping trip in London with his aunt. His aunt had gone into a cafe to get herself a latte, and Harry had been left outside. He was waiting around watching the people pass when a small floating demon passed by. He called them Fluffys', and he tracked its progress from his spot.

The fluffy had floated towards an Asian man and a Caucasian woman on the cafe patio, and the Asian man lifted his hand and swatted it away. Harry was stunned. He had thought he was the only person who could see them, besides the weird men and women in black that sometimes appeared.

"Blasted demons!" The Asian man cursed. "They flock to Japan but leave England alone. I swear if I could I would transfer here just to avoid exorcising them all the time."

Harry smiled. He was finally learning something about the things he saw.

"Yes, but then you would miss the thrill of the hunt and fight. I know you Takeshi, and you always complain but you are one of the first exorcists to jump into battle." The woman replied smiling at the man.

"That's because you can't trust the younger exorcists, all green and hardly a sensible bone in their bodies."

"Is that the product of their parents or their teachers?"

"Both! If their parents raised them right, and if they teachers were harder than we would have a fine line of exorcists ready to go, but instead he have a bunch of children playing a game they can't win. Of course there are a few every so often that are exceptional, but you can't always expect that and have to settle with what you got."

"Takeshi, I think we are being listened to." The woman announced.

Harry went rigid in fear. He could only imagine how angry they would be now that they caught him listening in. When a hand landed on Harry's shoulder, he jumped, and then froze in terror. The hand turned him around and he saw the chatting pair staring at him in contemplation.

"Listen Kid, you shouldn't eavesdrop. This is one conversation that will give you nightmares." The man warned him.

"I-I- I'm sorry, sir." Harry apologized, looking at the ground and refusing to meet their eyes.

"Boy! What have I told you about talking to strangers? Now come along." Aunt Petunia's screech broke through the air. Harry jumped again, but slipped out from under the man's hand.

"I-I already have nightmares a-about the demons sir." Harry whispered before turning and running after his aunt.

Harry was quickly caught up to his aunt, and even though he had been caught, he was happy. He now knew what the things he saw were called and where he could find people to help him- Japan and the exorcists.

o.O.o

Harry had taken to spending his recess time trying to find a way to get to Japan, or studying about exorcists. From what he had found, exorcists were people who helped others get rid of demons or spirits trying to steal their bodies. There was a bunch of words Harry didn't understand, but he figured it had to do with killing demons with hand gestures or speaking loudly.

Harry didn't have much luck on finding a way to Japan. He had asked his teacher and the woman had patted his head and simply told him that giant machines that flew in the sky could take him there if he had a valid passport, and the money to afford it.

Harry didn't know what a passport was, and he didn't have any money but he was determined to find another way to Japan. He looked at bus routes, but none of them went as far as Japan. He had found a map of the London underground but it didn't go to Japan either. He briefly wondered if a train from Kings Cross would take him there but when he had asked his teacher, she only laughed and gave him a pat on the head.

A month later, Harry finally found a way to Japan. Uncle Vernon had come home bragging about a conference in Japan that he had been invited to. Some Japanese company was looking to buy shares in Grunnings to help it expand, and Vernon was one of the few chosen to go meet them. Harry knew it was a sign, and started planning on how he would follow his Uncle to Japan.

Harry decided the best way to follow his uncle would be to do it unseen. So the night before Uncle Vernon left, Harry had cleared out some of his clothes, and snuck into his large bag. Harry curled up among the clothes and fell asleep, knowing that his Uncle Vernon would leave early in the morning and not notice that Harry wasn't in his cupboard.

Harry woke up when the bag he was in was roughly thrown into something. He was thinking the trunk. He heard his Uncle grumble about early flights, and time zones, but he ignored it. He was too excited about going to Japan to care.

Harry had fallen asleep again by the soft bumps in the road. He slept through Vernon checking his bag in, and even being loaded onto the flying machine. He was so warm and comfortable curled into his Uncle's clothes, that he barely responded to any of the hard jerks and rough landings the bag was subjected to.

Harry woke up when he felt the air get colder and colder. He curled into himself further, and shivered, but it wasn't working. Harry was losing feeling to his limbs, when he felt something wiggle against his side. Looking over he noticed a little red mouse.

He had seen this type of mouse demon before wandering the neighbourhood, and had even watched as one set fire to a house once. The mouse stared at Harry; before it opened, its mouth and a wave of heat enveloped Harry's body.

Harry smiled at the mouse and whispered a quiet thank you as the heat warmed his body and his shivering stopped. The mouse curled up on his shoulder and occasionally blew more heat around Harry to keep him worm the rest of the trip.

When they landed, the mouse gave a squeak and took off, leaving Harry alone. Harry smiled sadly after it, but waited. He didn't want to sneak out just yet and get caught, so he would listen for the perfect time. He felt as the bag was thrown around, and was infinitely grateful for the clothes that cushioned him.

Finally he heard his Uncle's voice, and perked up.

"Bloody foreigners, why can't they just learn the Queen's English like proper people? There was would be less war and more money if they just converted. Instead, I get lost in this blasted place and they give me weird looks. Bloody useless, the lot of them."

Harry didn't know what his uncle was talking about but he didn't care. He was finally in Japan. Harry felt himself being pushed along by his Uncle, and then loaded into another car. The ride was long, but when they stopped and Harry heard the car door opening, he knew it was almost time to escape.

His bag was lifted and placed down, and Harry prepared himself.

"Just watch my bags while I check in then I will pay you!" His Uncle ordered someone.

"Hai, Hai." Another person answered.

"Just stay there!"

Harry counted to 10 and then slowly undid the zipper. He peeked out and saw an Asian man smoking and watching to door to a hotel. Harry lowered the zipper more, and crawled out of the bag, happy he wasn't noticed.

Once out, he ran.

He ran down past tall buildings, people, bright lights, demons, and around cars. When he finally felt his legs grow tired, he stopped and bent over to catch his breath. He was free.

Harry stood up straight and finally took the time to appreciate the city he was in. He was finally going to get some answers, and he couldn't be happier. Only one problem.

When he tried to talk to someone they didn't understand him. Harry just learned that Japan spoke a different language than Britain.

What was he going to do?

Harry started wandering around, slowly growing more panicked as he realized he hadn't quite thought his plan through. He was in a new place where no one understood him; he had no money, nowhere to go, and no idea how to return to his uncle.

After an hour Harry came across a park, and sat on a bench and started to cry. He was hungry and lost, and he knew that he was going to finally die in the streets like his uncle had always told him would happen when he was older.

Suddenly a hand cupped his chin, and forced his face up. Harry saw a man in front of him in a weird white outfit and large white top hat.

"Poor child, why are you out here crying all alone?" The man asked. Harry instantly perked up.

"You speak English sir?"

"Of course child, I speak many languages. Now what is a cute little thing like you doing by yourself? If you're not careful someone might come along and eat you right up." The man said as he tapped Harry's nose repeatedly.

Harry felt his eye's watering more. "I came to Japan to find help with the demons sir, but now I'm lost and alone." Harry admitted. The man spoke English and Harry was hopeful that he could help.

"Demons you say?" The man grinned showing two very sharp canines.

"Yes, I see them and some are scary, but I heard that people in Japan know how to scare them off." Harry told the stranger.

"Yes there are people trained to deal with them..." The man trailed off.

"Exorcists sir."

"And how do you know about exorcists, little one?"

Harry felt his hope building as the man continued to ask him questions and not shoot down his theories.

"I heard a man in London talking about it, sir. I shouldn't have listened but he knew what the strange things I saw were called."

"Do you want to be an exorcist little one?" The man asked.

"I t-think so, sir." Harry wasn't sure if he wanted to be one, but he knew they could help.

"Well then you are in luck, because I just happen to be the Headmaster of a school that will teach you how to be an exorcist. I'm in town tonight to pick up another young boy who wants to learn."

"Really, sir?" Harry couldn't believe his luck.

"What is your name, and how old are you little one?"

"Harry Potter, sir, and I'm six years old."

"Well Mister Potter, I am Mephisto Pheles, and I'm afraid my age is far too big to share." The man, Mephisto, smiled again and took Harry's hand, pulling him off the bench and down the street.

"Now the boy we are going to meet is Yukio, and he is seven. I think you two will be great friends."

Harry stared at the man and smiled. He had been right; Japan was the right place to go.

o.O.o

Harry sat in his Demon Seals class, absently playing with the paper crane his best friend Yukio had made for him. They had been training to be exorcists for a year now, and Harry never regretted his decision to come to Japan.

"Harry you should really pay attention." Yukio whispered to him.

It had taken awhile but Harry had learned Japanese, with Yukio's help and some ritual on Mephisto's part.

"I'm sorry. I was just thinking about life a year ago." Harry whispered back.

"We met a year ago, and that was one of the best days of my life." Yukio responded, quickly squeezing Harry's hand before dropping it to take more notes.

Harry smiled at his friend, and started taking notes.

"It was the best day of my life too, Yukio."

o.O.o

"I just don't understand why he needs to get into so many fights!" A 9 year-old Yukio ranted as he paced inside a duelling chamber. "I know Rin tries to be good, but everyday it's the same thing."

"Do you think it has anything to do with his demon powers?" Harry asked.

"Maybe... I don't know... It's just... frustrating. I want him to do well, he wants to do well, but something happens and he's fighting all over again."

"It's only natural to worry over your brother Yukio. You can't always help those you love, but you can support them. Rin will find his path, and be happy, just like you." Harry consoled his friend.

"I guess you're right Harry. When did you get so wise?" Yukio asked, smiling for the first time that day.

"I have been spending too much time with your father. I think he's hoping that if he teaches me some wisdom, It will rub off on you." Harry teased.

"You think I'm not wise?" Yukio asked, pretending to be offended.

"I think a newborn baby holds more wisdom than you." Harry teased.

"Yes, not all of us are as wise and intelligent as you Mr. Follow-his-own-footsteps-and-fell-down-the-same-hill-twice."

Harry blushed and lightly pushed Yukio.

"I was tired; we had been in the field training for a week. Nothing looked the same after five seconds." Harry defended himself, his face bright red in embarrassment.

"And yet I never had the same problem." Yukio smugly pushed his glasses further up his nose."

"No, you only clung to Minozawa-sensei's side like a leech, scared that you would get lost." Harry responded.

It was Yukio's turn to blush, "I did not! I was asking his questions about the assignment and getting his insight on how we performed."

"Funny, I don't remember you asking any questions." Harry raised a single eyebrow.

"If you boys are down pulling pigtails, we can start this healing class." Minozawa-sensei said from the door.

Harry and Yukio straightened up and bowed to their instructor.

"Good Afternoon, Minozawa-sensei." They said together.

"Sit, today we will be looking at how to deal with major penetration wounds..."

o.O.o

A 10 year-old Harry stood on the edge of a field swarming with demons. Yukio stood at his side, calmly watching the writhing mass that tried to approach them.

"Ready?" Yukio asked.

"Sometimes I think you like fighting just as much as Rin does." Harry teased.

"I fight with demons, not like a demon." Yukio grinned. "But really, ready?"

"Whenever you are." Harry responded taking out four pieces of papers.

Harry bit his thumb and smeared blood across the magical circles, summoning four giant red mice like demons. "Guard Yukio, and take as many demons as you can down." Harry ordered.

Yukio gave him a curt nod before he started running towards the demons, taking out his guns and shooting. Harry's mice stood at his sides, breathing long blasts of fire at the demons rushing to get Yukio.

Harry watched as his best friend shot down numerous demons, continuously reloading his gun.

"Are you just going to stand there?" Yukio yelled shooting a demon that got too close in the head.

Harry gave his friend a small smile, before he reached behind his back and pulled out a demon blade. Harry rushed into the field, swinging his sword and chopping down demons as he went.

When he made it to Yukio, his friend laughed and muttered a quiet "About time."

o.O.o

An 11 year-old Harry clutched Yukio's hand in his own as they stared at the Heavy wooden doors. They were graduating today and becoming full exorcists. Soon the doors would open and they would walk in and declared Meisters.

Harry's hands felt sweaty, and his mind was buzzing, but holding his friends hand grounded him.

"It won't be bad... just a little ceremony right?" Yukio anxiously asked.

"Fujimoto-sama said it was a very painless process..." Harry tried to reassure.

"Well you're his favourite so I'm sure you will be fine." Yukio said with a nervous laugh.

"And you're his son. I think he would be more careful with you."

"I'm not really his son." Yukio tried to argue.

"What is a father? I think it is a man who raises you, loves you, and teaches you to be the best person you can. Has Fujimoto not done that for you? I think he has, and therefore you are his son." Harry countered.

"How ever did you get so wise?" Yukio asked, happier than he was before.

"Well someone has to be wise enough for the both of us." Harry smiled.

The doors opened, and Harry and Yukio gripped their hands tighter together.

"Ready?"

"Whenever you are."

o.O.o

A 13 year-old Harry was lovingly cleaning his demon blade when Yukio rushed into his room. Looking up Harry could see the distress on his friends face, quickly putting away his blade, Harry stood and wrapped his arms around Yukio.

"Yukio, what's wrong?"

"H-he's dead." Yukio stuttered before he burst into hysterical tears. "It's Rin's fault I just know it! Father was always able to hold off Satan, but Rin did something!" Yukio screamed.

Harry ushered the taller boy over to the bed and sat them down. "Fujimoto-sama is dead?" Harry asked, in a stunned state.

"I w-went over to the church and it was a disaster. Father was dead, the place was a mess ,and ... God I just know it was Rin's fault." Yukio cried. "He can't stay out of trouble, he can't hold a job, and the only thing he was good at was hurting father! God, why couldn't he have just tried harder?"

"It's okay Yukio, just let it all out. I'm here for you." Harry whispered.

"What would I do without you Harry?" Yukio asked as he buried his face into Harry's neck and cried. "What would I do without you?"

Harry spent the night comforting Yukio over his friend's death. Father Fujimoto was a great man and exorcist. He was well respected and loved by many, and he would leave a huge hole behind that no other could fill.

The next morning Harry woke to Yukio climbing out of bed.

"Kio?" Harry said in a sleepy tone.

"Go back to sleep Harry. I just need to go back to the church and help with Father's funeral." Yukio explained.

"I'll stop by later and help." Harry offered.

"Thanks Harry, and thanks for last night."

"It was nothing Yukio, what are best friends for?"

Yukio smiled before he left. Harry rolled over and stared at the ceiling, wondering how he could help his friend through this tough time. It would be hard, but Harry would do everything and anything for Yukio.

o.O.o

A few days after Fujimoto's funeral, Harry and Yukio stood in the hallway of the exorcist school building. They were holding hands and each staring at a door.

"Rin is in there." Harry stated.

"I know."

"He's going to be shocked and upset." Harry told his friend.

"I know."

"He will want to talk."

"Probably."

"Right away and probably won't let you teach."

"Sounds like him."

"Are you ready for this Mr. Pharmaceutical-Herb Professor?" Harry asked.

"Whenever you are, Mr. Pharmaceutical-Herb Professor." Yukio responded, holding Harry's hand tighter as he opened the door to their classroom for the first time.

The End. But Possibly TBC...

So what did you think?

Short I know, but I figured I would use this as a sampler and get the general feel for the fandom.